diff --git a/requirements.txt b/requirements.txt
index 3eb8e94..861b40a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -28,7 +28,7 @@ Markdown==3.1.1
 nose==1.3.7
 numpy==1.17.1
 pkginfo==1.5.0.1
-protobuf==3.9.1
+protobuf==3.15.0
 pycodestyle==2.5.0
 Pygments==2.4.2
 python-dateutil==2.8.0